Method and apparatus for laser assisted cataract surgery

ABSTRACT

Devices and methods for use in laser-assisted surgery, particularly cataract surgery. Specifically, the use of an optical fiber with a proximal and distal end, wherein the distal end has a non-orthogonal angle with the diameter of the optical fiber, to create an off-axis steam bubble for cutting and removing tissue in an operative region. Where the optical fiber is bent, rotating the fiber creates a circular cutting path for the steam bubble, allowing access to tissues that may normally be blocked by obstructions and obstacles.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application 8 claims benefit of U.S. Provisional Application Ser.No. 61/865,454 (Attorney Docket No. 41663-710.101), filed Aug. 13, 2013,the entire contents of which is incorporated herein by reference.

FIELD OF THE INVENTION

The field of the present application pertains to medical devices. Moreparticularly, the field of the invention pertains to an apparatus,system, and method for laser assisted cataract surgery.

BACKGROUND OF THE INVENTION

A “cataract” is a clouding of the lens in the eye that affects vision.Most people develop cataracts due to aging. The condition is notuncommon; it is estimated more than half of all Americans will eitherhave a cataract or have had cataract surgery by age 80.

FIG. 1 is a diagram of the human eye, included for background. The majorfeatures of the eye 100 comprise the cornea 101, the anterior chamber102, the iris 103, the lens capsule 104, the lens 105, the vitreous 106,the retina 107, and the sclera 108. The lens capsule 104 has an anteriorsurface 109 bordering the anterior chamber 102 and a posterior surface110 bordering the vitreous 106. Most relevant to cataracts, the lens 105within the lens capsule 104 is comprised of a nucleus 111 and cortex112.

As shown in FIG. 1, the lens 105 within the eye 100 lies behind the iris103. In principle, it focuses light onto the retina 107 at the back ofthe eye 100 where an image is recorded. The lens 105 also adjusts thefocus of the eye 100, allowing it to focus on objects both near and far.

The lens 105 contains protein that is precisely arranged to keep thelens 105 clear and allow light to pass through it. As the eye ages, theprotein in the lens 105 may clump together to form a “cataract”. Overtime, the cataract may grow larger and obscure a larger portion of thelens 105, making it harder for one to see.

Age-related cataracts affect vision in two ways. The clumps of proteinforming the cataract may reduce the sharpness of the image reaching theretina 107. The clouding may become severe enough to cause blurredvision. The lens 105 may slowly change to a yellowish/brownish tint. Asthe lens 105 ages, objects that once appeared clear may gradually appearto have a brownish tint. While the amount of tinting may be small atfirst, increased tinting over time may make it more difficult to readand perform other routine activities.

Surgery is currently the only real treatment for cataracts. Each year,ophthalmologists in the United States perform over three millioncataract surgeries. The vast majority of cataracts are removed using aprocedure called extracapsular cataract extraction (ECCE). ECCEtraditionally comprises of several steps. Incisions must first be madeto the cornea 101 in order to introduce surgical instruments into theanterior chamber 102. Through the incisions in the cornea 101 and thespace of the anterior chamber 102, the surgeon may remove the anteriorface of the lens capsule 109 in order to access the lens underneath 105.This phase of the surgery, known as capsulorhexis, is often the mostdifficult procedure in ECCE.

Having gained access to the lens through capsulorhexis, a small amountof fluid may be injected into the exposed lens capsule 104 to improveaccess and maneuverability of the lens 105. This phase of the surgery isknown as hydrodissection to the skilled artisan.

After loosening the lens, it must be extracted. Traditionally, the lensis manually extracted through a large (usually 10-12 mm) incision madein the cornea 101 or sclera 108. Modern ECCE is usually performed usinga micro surgical technique called phacoemulsification, whereby thecataract is emulsified with an ultrasonic handpiece and then suctionedout of the eye through incisions in the cornea 101.

A phacoemulsification tool may be an ultrasonic handpiece with atitanium or steel needle. The tip of the needle may vibrate at anultrasonic frequency to sculpt and emulsify the cataract while a pumpaspirates particles through the tip. In some circumstances, a secondfine steel instrument called a “chopper” may be used to access thecataract from a side port to help with “chopping” the nucleus 111 intosmaller pieces. Once broken into numerous pieces, each piece of thecataract is emulsified and aspirated out of the eye 100 with suction.

As the nucleus 111 often contains the hardest portion of the cataract,emulsification of the nucleus 111 makes it easier to aspirate theparticles. In contrast, the softer outer material from the lens cortex112 may be removed using only aspiration. After removing the lensmaterial from the eye 100, an intraocular lens implant (IOL) may beplaced into the remaining lens capsule 104 to complete the procedure.

One variation on phacoemulsification is sculpting and emulsifying thelens 105 using lasers rather than ultrasonic energy. In particular,femtosecond laser-based cataract surgery is rapidly emerging as apotential technology that allows for improved cornea incision formationand fragmentation of the cataract.

Phacoemulsification and laser-based emulsification, however, still havetheir shortcomings. Phacoemulsification requires the use of tools thatpropagate ultrasound energy along the length of the tool, from aproximal transducer to a distal tip. The propagation leads to thetransmission of ultrasound energy along the tool to other tissuesproximal to the eye 100. Ultrasound tools also generate more heat thanwould be desirable for a procedure in the eye 100. In addition, themechanical requirements of propagating the ultrasound wave along thelength of the tool often make it rigid and difficult to steer aroundcorners or bends.

Laser-based tools have their own drawbacks. Presently, manuallycontrolled lasers require careful, precise movement since they caneasily generate unwanted heat in the eye 100. Laser fibers in the toolare also fragile, and thus easily damaged when attempting to navigatetight corners. Both limitations increase surgery time and raise safetyconcerns.

An alternative to conventional laser systems, femtosecond laser systemshave their advantages and drawbacks as well. Femtosecond laser systemsmay be used to create entry sites through the cornea 101 and sclera 108into the eye 100, as well as to remove the anterior face of the capsule104. Femtosecond laser energy may be focused within the lens nucleus 111itself, and used to “pre-chop” the lens nucleus 111 into a number ofpieces that can then be easily removed with aspiration. Femtosecondlasers, however, can only fragment the central portion of the lens 105because the iris 103 blocks the peripheral portion of the lens 105.Thus, use of another emulsification technology—ultrasound orconventional laser—is still necessary to fracture and remove theperipheral portion of the cataract in lens 105, extending totalprocedure time. Furthermore, femtosecond laser systems are alsoexpensive and costly to operate and maintain.

As an alternative to a purely laser-based emulsification, certainsystems may use the lasers to generate steam bubbles to createshockwaves to break up the cataract material during emulsification.

FIG. 2 is a diagram of a multimode optical fiber 200 with a flat tip atthe distal end 201, included for illustration purposes. At the output ofthe distal end 201, all laser energy originating from laser source 203,and carried through optical fiber 200, is absorbed at the surface offiber 200. If the laser energy is high enough, the surrounding water mayvaporize and form a steam bubble 202. If the laser continues to outputenergy, the steam bubble 202 may grow into a cylindrical shape. Acylindrically-shaped steam bubble only occurs when the absorption depthin the water is relatively short; light energy with a wavelength near 3μm can produce a cylindrically shaped steam bubble while light energynear 2 μm does not. The cylindrically-shaped steam bubble 202 produces amechanical action that can cut or disrupt tissue.

FIG. 3 is a diagram of a multimode optical fiber 300 with a tapered(cone shaped) tip at the distal end 301, included for illustrationpurposes. At the output of the distal end 301 of optical fiber 300, allthe laser energy may be absorbed at the surface of the cone shapedfiber. If the laser energy is high enough, the water vaporizes and formssteam bubble 302. If the laser continues to output energy, then thesteam bubble can grow into a spherically-shaped steam bubble. Thedynamics of steam bubble generation can be found in “Effect ofmicrosecond pulse length and tip shape on explosive bubble formation of2.78 μm Er,Cr;YSGG and 2.94 μm Er:YAG laser”, Paper 8221-12, Proceedingsof SPIE, Volume 8221 (Monday 23 Jan. 2013).

In both FIGS. 2 and 3, the steam bubbles generated by the optical fibersare collinear with the optical fiber. Being collinear, the orientationof the steam bubbles relative to the optical fibers create problems incertain applications. For example, during capsulorhexis, where theanterior portion of the lens capsule is removed, the orientation of thesteam bubble presents a challenge because the tools are oriented at asteep angle to the lens capsule through incisions at the edge of thecornea.

Therefore, it would be beneficial to have a new method, apparatus, andsystem for using steam bubbles that are not collinear with the neutralaxis of the optical fiber.

SUMMARY OF THE INVENTION

In general, the present invention provides a device and method for laserassisted cataract surgery using laser energy emitted by optical fibersto create steam bubbles. In one aspect, the present invention providesfor a surgical device comprising an optical fiber having a proximal endand distal end, wherein the optical fiber is configured to generate asteam bubble from light energy conveyed out the distal end of the fiber,the proximal end is operatively connected to a light source, and thedistal end comprises a tip with a non-orthogonal tilted edge across thediameter of the fiber.

A related device further comprises a tube that encloses the opticalfiber. In some embodiments, the tube is pre-bent at a predeterminedangle. In some embodiments, an angle of the tilted edge exceeds 45degrees. In some embodiments, an angle of the tilted edge does notexceed 45 degrees. In some embodiments, the angle of the tilted edgeexceeds 7 degrees but not 45 degrees. In some embodiments, the opticalfiber is further configured to generate a second steam bubble from theapplication of laser energy.

In another aspect, the present invention provides for a method thatcomprises transmitting light energy through an optical fiber, generatinga steam bubble; and directing the steam bubble to an operative region ofa patient, wherein the optical fiber has a proximal end and a distalend, the optical fiber being configured to generate the steam bubblefrom light energy conveyed out the distal end of the fiber, the proximalend being operatively connected to a light source, and the distal endcomprising a tip with a non-orthogonal tilted edge across the diameterof the fiber.

In related embodiments, the optical fiber is enclosed within a tube. Insome embodiments, the tube is pre-bent at a predetermined angle. In someembodiments, the method further comprises axially rotating the tube togenerate a circular cutting path for the steam bubble. In someembodiments, axially rotating the optical fiber to generate a circularcutting path for the steam bubble. In some embodiments, an angle of thetilted edge exceeds 45 degrees. In some embodiments, an angle of thetilted edge does not exceed 45 degrees. In some embodiments, the angleof the tilted edge exceeds 7 degrees but not 45 degrees.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described, by way of example, and with referenceto the accompanying diagrammatic drawings, in which:

FIG. 1 illustrates the portions of the human eye, included forbackground;

FIG. 2 illustrates a multimode optical fiber with a flat tip at thedistal end, included for illustration purposes;

FIG. 3 illustrates a multimode optical fiber with a tapered (coneshaped) tip at the distal end, included for illustration purposes;

FIGS. 4A-4B illustrate an optical fiber coupled to a laser sourceconsistent with the prior art, included for explanative purposes;

FIGS. 5A-5B illustrate an optical fiber coupled to a laser source inaccordance with an embodiment of the present invention;

FIGS. 6A-6B illustrate an optical fiber coupled to a laser source wherea steam bubble may be deflected from the axis of the fiber byincorporating a fiber with tilted end and a laser source with high waterabsorption, in accordance with an embodiment of the present invention;

FIGS. 7A-7B illustrate an optical fiber coupled to a laser source wherea steam bubble may be deflected from the axis of the fiber byincorporating a fiber with a tilted end at 35 degrees, in accordancewith an embodiment of the present invention;

FIGS. 8A-8B illustrate an optical fiber with a tip with a tilt angle of45 degrees, in accordance with an embodiment of the present invention;

FIGS. 9A-9B illustrate an optical fiber with a tip with a tilt angle of50 degrees, in accordance with an embodiment of the present invention;

FIGS. 10A-10B illustrate an embodiment of the present invention wherethe steam bubble is deflected from the axis of the fiber byincorporating a laser source with high water absorption, a bent opticalfiber, and a tilted tip;

FIGS. 11A-11B illustrate an embodiment of the present invention wherethe steam bubble is deflected at an angle of 35 degrees from the axis ofthe fiber by incorporating a laser source with high water absorption, abent optical fiber, and a tilted tip;

FIGS. 12A-12B illustrate an embodiment of the present invention wherethe steam bubble is deflected from the axis of the fiber byincorporating a laser source with high water absorption, a bent opticalfiber, and a tilted end at the fiber; and

FIGS. 13A-13B illustrate an embodiment of the present invention wherethe steam bubble only exits from the side from a bent optical fiber witha tilted end at the fiber.

DETAILED DESCRIPTION OF THE INVENTION

Although certain preferred embodiments and examples are disclosed below,inventive subject matter extends beyond the specifically disclosedembodiments to other alternative embodiments and/or uses, and tomodifications and equivalents thereof. Thus, the scope of the claimsappended hereto is not limited by any of the particular embodimentsdescribed below. For example, in any method or process disclosed herein,the acts or operations of the method or process may be performed in anysuitable sequence and are not necessarily limited to any particulardisclosed sequence. Various operations may be described as multiplediscrete operations in turn, in a manner that may be helpful inunderstanding certain embodiments; however, the order of descriptionshould not be construed to imply that these operations are orderdependent. Additionally, the structures, systems, and/or devicesdescribed herein may be embodied as integrated components or as separatecomponents.

As is known in the art, the conveyance of light energy at an interfaceof two materials is affected by the angle of incidence of the lightenergy, the index of refraction of the two substances, and the criticalangle of the interface. When light is travelling from a high index ofrefraction material to a low index of refraction material and the angleof incidence is below the critical angle, the light largely passes fromthe high index of refraction to a low index of refraction material. Whenlight is travelling from a high index of refraction material to a lowindex of refraction material and the angle of incidence is above thecritical angle, the light reflects off the interface. If some of thelight is greater than the critical angle, the light will exit the fiberfrom the side of the fiber. If all of the light in the fiber hits thetitled end at greater than the critical angle, then all of the lightwill exit the side of the fiber.

Higher index materials have correspondingly smaller critical angles. Forexample, for light coming from fused silica into air, the critical angleis 44.6 degrees. In contrast, the critical angle in water is lower.

FIG. 4 illustrates an optical fiber 402 coupled to a laser source 401consistent with the prior art, included for explanative purposes. Asshown in FIG. 4A specifically, the conveyance of laser energy into andout of the optical fiber 402 contemplates two acceptance angles: (a) theangle required for light traveling down a multimode optical fiber toremain in the fiber, and (b) the angle of the laser energy exiting theend of the fiber. Thus, laser energy traveling at angles greater thanthe fiber's acceptance angle 404 exits the fiber 402 prior to reachingthe distal end 403. When the laser energy exits the optical fiber 402,the acceptance angle is represented by 405.

FIG. 4B illustrates the distal end 403 of optical fiber 402 consistentwith the prior art, included for explanation purposes. As shown in FIG.4B, the tip of the distal end 403 is formed by an orthogonal cut acrossthe diameter of the optical fiber 402. The cut forms an approximately aright angle, i.e., ninety degrees, with the length of the optical fiber402. In other words, the plane formed at the tip of distal end 403 isapproximately orthogonal to the longitudinal axis of the optical fiber402.

In some applications including the cutting of membranes, it is desirableto have the steam bubble perpendicular to the surface of the membrane.Thus, in some embodiments, the ability to add steam bubble deflection tothe fiber can allow for sharper bends of the steam bubble relative tothe membrane surface since fibers have a finite bending radius.

FIG. 5 is a diagram of an optical fiber coupled to a laser source, inaccordance with an embodiment of the present invention. Similar to FIG.4, laser source 501 emits laser (light) energy into optical fiber 502for transmission into the operative region. Being an optical fiber, theconveyance of laser energy into and out of the optical fiber 502contemplates two acceptance angles: (i) the angle required for lighttraveling down a multimode optical fiber to remain in the fiber (504),and (ii) the angle of the laser energy exiting the end of the fiber(505).

In contrast to FIG. 4, FIG. 5 specifically shows the effect of having atilt angle 506 at the tip of the distal end 503 of optical fiber 502.The angle of refraction 508 of the interface may be computed usingSnells' law and the index of refraction of the two medium. The effect ofthe tilted distal end 503 and the angle of refraction 508 produce anangle of deflection 509 from the axis of the optical fiber 502. Thelight will exit from the tilted end of the fiber provided that the sumof the tilt angle 507 and acceptance angle 505 do not exceed thecritical angle 510.

FIG. 5B illustrates the distal end 503 of optical fiber 502. As shown inFIG. 5B, the tip of the distal end 503 is formed by a non-orthogonal cutacross the diameter of the optical fiber 502. The angle of the cut formsa non-right angle 510 with the length of the optical fiber. The adjacentangle 511 is identical to tilt angle 507 from FIG. 5A due to the rulesof Euclidean geometry.

The preferred embodiments generally use laser light with a shortabsorption depth in water, i.e., an absorption depth less than 20 μm,which requires a corresponding absorption coefficient greater than 500cm⁻¹. Accordingly, the preferred embodiments make use of light energywith either (i) a wavelength shorter than 200 nm or (ii) a wavelengthlonger than 2.8 μm. Among the options with wavelengths longer than 2.8μm, light with wavelengths of 3 μm, 4.5 μm, 6 μm and 10 μm may beespecially effective in certain embodiments. In particular, light with awavelength of 3 μm may be advantageous because its absorption depth isvery short and appropriate optical fibers are inexpensive. In contrast,optical fibers capable of conveying light energy of 4.5 μm, 6 μm, and 10μm wavelength are more costly.

The preferred embodiments also make use of pulsed light energy. In someembodiments, the pulse width may be as long as 500 μs. Enhancedperformance has been observed in embodiments that make use of pulsewidths of 80 μs in length and shorter. Some embodiments make use oflight energy with a pulse width of 60 μs.

FIG. 6 is a diagram of an optical fiber coupled to a laser source wherea steam bubble may be deflected from the axis of the fiber byincorporating a fiber with tilted end and a laser source with high waterabsorption, in accordance with an embodiment of the present invention.The embodiment may be used to facilitate cataract surgery or anysurgical application that involves cutting tissue. In some embodiments,the formation and collapse of the steam bubble may generate adirectional shock wave.

The advantages of having a deflected steam bubble include (i) being ableto reach locations that the tip of the optical fiber cannot reach, (ii)being able to deflect by rotation the fiber, (iii) being able to use thedefection angle to add to mechanical bends of the optical fiber, and(iv) improving the surgeon's line of sight of the operative region andcutting process.

In FIG. 6A, optical fiber 601 conveys laser energy from laser source 602to the tilted tip 603 at the distal end of the optical fiber 601. Tiltedtip 603 is shaped to tilt angle 604. In FIG. 6A, tilt angle 604 is setto 20 degrees. Laser energy conveyed down the optical fiber 601 from thelaser source 602 generates steam bubble 605. Steam bubble 605 isoff-angle from the neutral axis of optical fiber 601, directed at adeflection angle 606. The combination of the tilted distal end 603 andthe angle of refraction 607 produce the angle of deflection 606 from theaxis of the optical fiber 601.

In FIG. 6B, optical fiber 601 may be subject to axial rotation 608 toform circular cutting path 609 with the deflected steam bubble 605. Thecircular cutting path 609 has the advantage of cutting holes with alarger diameter than fiber 601 itself.

FIG. 7 is a diagram of an optical fiber coupled to a laser source wherea steam bubble may be deflected from the axis of the fiber byincorporating a fiber with a tilted end at 35 degrees, in accordancewith an embodiment of the present invention. Similar to FIG. 6A, opticalfiber 701 conveys laser energy from laser source 702 to tilted tip 703at the distal end of optical fiber 701. Tilted tip 703 is shaped to a 35degree tilt angle 704. Laser energy conveyed down optical fiber 701 fromlaser source 702 generates steam bubble 705. The effect of tilted distalend 703 and angle of refraction 707 produce an angle of deflection 706from the axis of optical fiber 701.

With a tilt angle 704 of 35 degrees, the tip of steam bubble 705 extendsout well beyond the diameter of the fiber 701. The deflection angle 706allows the surgeon to cut the surface of the lens capsule while alsokeeping the fiber 701 parallel to the surface of the lens capsule,improving visibility of the operative region. This helps a surgeon seethe location of the fiber tip 703 while cutting material below the fibertip 703.

In FIG. 7B, optical fiber 701 may be subject to axial rotation 708 toform circular cutting path 709 using deflected steam bubble 705. Asdiscussed earlier, the circular cutting path 709 has the advantage ofcutting holes in the material with a larger diameter than the fiber 701itself. Specifically, steam bubble 705 has a larger 35 degree tilt atits tip 703 that creates a larger circular cutting path 709 from therotation of the optical fiber 701.

FIG. 8 is a diagram of an optical fiber 801 with a tip 802 with a tiltangle of 45 degrees, in accordance with an embodiment of the presentinvention. In practice, some light exits the tilted tip 802 and somelight exits the side of fiber 801 because the critical angle of fusedsilica is 44.6 degrees in air and slightly lower in water. The light infiber 801 that is below the critical angle and is refracted through thetilted surface and the laser light forms a steam bubble 803 at tiltedtip 802. The light in the fiber 801 that is above the critical angle isreflected off of the surface of tilted tip 802 and exits the side of thefiber 801. This reflected laser energy forms a steam bubble 804 directedout the side of the fiber 801. Thus steam bubbles 803, 804 are formed,both of which may be used to cut in two locations at once. By carefullyselecting the angle of the tilted tip 802, the relative size and powerof the steam bubbles 803, 804 can be controlled. In some embodiments,steam bubbles 803 and 804 may merge due to their close proximity to eachother.

FIG. 8B is a diagram of optical fiber 801 with fiber rotation 805, inaccordance with an embodiment of the present invention. Rotation 805moves steam bubbles 803, 804 in a circular cutting path 806 around thefiber 801 to improve cutting and removal of targeted material. Althoughtilted tip 802 is 45 degrees, in other embodiments, a different angledtip may create a different circular cutting path in other embodiments.

FIG. 9 is a diagram of an optical fiber 901 with a tip 902 with a tiltangle of 50 degrees, in accordance with an embodiment of the presentinvention. In FIG. 9A, when surrounded by air or water, the tilt angleof tip 902 exceeds the critical angle. Thus, in both situations most ofthe light exits through the side of the fiber 901 due to internalreflection. Consequently, only a single steam bubble 903 is formed outthe side of the fiber 901.

FIG. 9B is a diagram of optical fiber 901 with fiber rotation 904, inaccordance with an embodiment of the present invention. Rotation 904moves steam bubble 903 in a circular cutting path 905 around the fiber901 to improve the cutting reach of the steam bubble 903.

In some embodiments, the size of the resulting steam bubbles may bealtered by changing the input angle of the laser energy into the fiber.If the laser light is input into the fiber with a small divergence fromthe neutral axis of the fiber, laser light will tend to exit the end ofthe fiber. If the laser light is input into the fiber with a smalldivergence at an angle with respect the axis of the fiber, the lightwill tend to exit the side of the fiber.

FIG. 10 illustrates an embodiment of the present invention where thesteam bubble is deflected from the axis of the fiber by incorporating alaser source with high water absorption (not shown), a bent opticalfiber 1001, and a tilted tip 1002. In FIG. 10A, the deflection angle1004 of the steam bubble 1003 may be added to the bend angle 1005 of thefiber 1001. The total angle of the steam bubble 1003 relative to thestart of the fiber 1001 is the sum of the deflection angle 1004 and thefiber bend angle 1005. In some embodiments, the bend angle 1005 may bemaintained by a bent tube around the bent optical fiber 1001.

FIG. 10B illustrates the use of bent optical fiber 1001 and tilted tip1002 with a rotation 1006. With rotation 1006, the net deflection angleof the steam bubble 1003 may be modified from the sum of fiber bendangle 1005 and deflection angle 1004 to the net of the deflection angle1004 subtracted from fiber bend angle 1005 by rotation of the fiber. InFIG. 10, the deflection angle 1004 is 20 degrees. Other embodiments mayhave different deflection angles and bend angles. Different anglescreate different circular cutting paths should the fiber be rotated. Insome embodiments, where bent optical fiber 1001 is enclosed by a bentouter tube, a circular cutting path may be created by axially rotatingthe bent outer tube, which yields more net deflection angles andaccesses more operative regions.

FIG. 11 illustrates an embodiment of the present invention where thesteam bubble is deflected at an angle of 35 degrees from the axis of thefiber by incorporating a laser source with high water absorption (notshown), a bent optical fiber 1101, and a tilted tip 1102. Similar toFIG. 10A, in FIG. 11A, the deflection angle 1104 of the steam bubble1103 is added to the bend angle 1105 of the fiber 1101. The total angleof the steam bubble 1103 relative to the start of the fiber 1101 is thesum of the deflection angle 1104 and the fiber bend angle 1105. In someembodiments, the bend angle 1105 may be maintained by a bent tube aroundthe bent optical fiber 1101.

FIG. 11B illustrates the use of bent optical fiber 1101 and tilted tip1102 with a rotation 1106. In FIG. 11B, the net deflection angle of thesteam bubble 1103 may be modified by rotation of the fiber 1101. In someembodiments, where bent optical fiber 1101 is enclosed by a bent outertube, a circular cutting path may be created by axially rotating thebent outer tube to yield even more net deflection angles and accessdifferent operative regions.

FIG. 12 illustrates an embodiment of the present invention where thesteam bubble is deflected from the axis of the fiber by incorporating alaser source with high water absorption, a bent optical fiber, and atilted end at the fiber. In FIG. 12A, because the tilt angle of the tip1202 is less than the critical angle, steam bubbles 1203, 1206 areformed from both the tilted tip 1202 and the side of the tip of thefiber 1201. The deflection angle 1204 of the steam bubbles are added tothe bend angle 1205 of the fiber 1201. Combined with bend angle 1205,the steam bubble 1206 may be directed behind the tip 1202. In someembodiments, this provides an advantage of being able to cut materialbehind corners or behind the tip 1202 of the fiber 1201. In someembodiments, the bend angle 1205 may be maintained by a bent tube aroundthe bent optical fiber 1201.

FIG. 12B illustrates the use of fiber 1201 and tilted tip 1202 withrotation 1207. In FIG. 12B, the rotation 1207 of fiber 1201 producescutting paths 1208 and 1209 in front of and along the side of the fiberdue to the combination of the steam bubbles 1203 and 1206. These cuttingpaths have the advantage of removing a large volume of material in asingle rotation. In some embodiments, where bent optical fiber 1201 isenclosed by a bent outer tube, a circular cutting path may be created byaxially rotating the bent outer tube to yield even more net deflectionangles and access different operative regions.

FIG. 13 illustrates an embodiment of the present invention where theresulting steam bubble exits from the side from a bent optical fiberwith a tilted end at the fiber. In FIG. 13A, the tilt angle 1302 of thetip 1302 exceeds the critical angle, resulting in a steam bubble 1303that exits from the side of the fiber 1301. In some embodiments, thebend angle 1304 may be maintained by a bent tube around the bent opticalfiber 1301.

FIG. 13B illustrates the use of fiber 1301, tilted tip 1302, and steambubble 1303 with rotation 1305, in accordance with an embodiment of thepresent invention. In this embodiment, rotation 1305, in combinationwith the bend angle 1304 and the length of the steam bubble 1303,produces a wide cutting path 1306. In some embodiments, where bentoptical fiber 1301 is enclosed by a bent outer tube, a circular cuttingpath may be created by axially rotating the bent outer tube to yieldeven more net deflection angles and access different operative regions.

The bending of the fiber can be achieved by numerous methods, such aspre-bent glass fibers and fibers bent in an outer tube. In someembodiments, bend fibers may be dynamically controlled. In certainembodiments, those bend fibers may be dynamically bent in a roboticallycontrolled tube mechanism. In other embodiments, the fibers may be bentby a robotically controlled flexure mechanism.

The present invention is not limited to embodiments using theaforementioned systems and the associated instrument drive mechanisms.One skilled in the art would appreciate modifications to facilitatecoupling to different robotic arm configurations.

For purposes of comparing various embodiments, certain aspects andadvantages of these embodiments are described. Not necessarily all suchaspects or advantages are achieved by any particular embodiment. Thus,for example, various embodiments may be carried out in a manner thatachieves or optimizes one advantage or group of advantages as taughtherein without necessarily achieving other aspects or advantages as mayalso be taught or suggested herein.

Elements or components shown with any embodiment herein are exemplaryfor the specific embodiment and may be used on or in combination withother embodiments disclosed herein. While the invention is susceptibleto various modifications and alternative forms, specific examplesthereof have been shown in the drawings and are herein described indetail. The invention is not limited, however, to the particular formsor methods disclosed, but to the contrary, covers all modifications,equivalents and alternatives thereof.

What is claimed is:
 1. A surgical device comprising: an optical fiberhaving a proximal end and distal end, wherein the optical fiber isconfigured to generate a steam bubble from light energy conveyed out thedistal end of the fiber, the proximal end is operatively connected to alight source, and the distal end comprises a tip with a non-orthogonaltilted edge across the diameter of the fiber.
 2. The device of claim 1,further comprising a tube that encloses the optical fiber.
 3. The deviceof claim 2, wherein the tube is pre-bent at a predetermined angle. 4.The device of claim 1, wherein an angle of the tilted edge exceeds 45degrees.
 5. The device of claim 1, wherein an angle of the tilted edgedoes not exceed 45 degrees.
 6. The device of claim 5, wherein the angleof the tilted edge exceeds 7 degrees.
 7. The device of claim 1, whereinthe optical fiber is further configured to generate a second steambubble from the application of laser energy
 8. A method comprising:transmitting light energy through an optical fiber; generating a steambubble; and directing the steam bubble to an operative region of apatient; wherein the optical fiber has a proximal end and a distal end,the optical fiber being configured to generate the steam bubble fromlight energy conveyed out the distal end of the fiber, the proximal endbeing operatively connected to a light source, and the distal endcomprising a tip with a non-orthogonal tilted edge across the diameterof the fiber.
 9. The method of claim 8, wherein the optical fiber isenclosed within a tube.
 10. The method of claim 9, wherein the tube ispre-bent at a predetermined angle.
 11. The method of claim 9, furthercomprising axially rotating the tube to generate a circular cutting pathfor the steam bubble.
 12. The method of claim 8, further comprisingaxially rotating the optical fiber to generate a circular cutting pathfor the steam bubble.
 13. The method of claim 8, wherein an angle of thetilted edge exceeds 45 degrees.
 14. The method of claim 8, wherein anangle of the tilted edge does not exceed 45 degrees.
 15. The method ofclaim 14, wherein the angle of the tilted edge exceeds 7 degrees.